Calcareous shell and structure of reef organisms are known to contain significant amount of strontium which is  absorbed during calcification and through other biological pathways.

It also plays an important role by accelerating coral and calcareous algae growth.

NSW contains approx. 7 - 9 mg/L strontium, making it the fifth most abundant cation in seawater.

Since the growth of corals and calcareous algae goes hand in hand with strontium and calcium depletion, depletion of calcium usually means depletion of strontium as well.

It is advisable to maintain a strontium concentration between 5 and 20 mg/L.